(function (doc, win) {
  // 分辨率Resolution适配
  var docEl = doc.documentElement,
  resizeEvt = 'orientationchange' in window ? 'orientationchange' : 'resize',
  recalc = function () {
  var clientWidth = docEl.clientWidth;
  if (!clientWidth) return;
  docEl.style.fontSize = 100 * (clientWidth / 750) + 'px';
  };
  
  // Abort if browser does not support addEventListener
  if (!doc.addEventListener) return;
  win.addEventListener(resizeEvt, recalc, false);
  win.addEventListener('pageshow', recalc, false);
  doc.addEventListener('DOMContentLoaded', recalc, false);
  })(document, window);